System and method for testing heat exchange performance of air cooler

Abstract

The invention relates to an air cooler heat exchange performance test system and a test method, which are characterized in that the test system comprises an air pressure simulation loop for simulating the air cooler to be in different air pressures, a temperature simulation assembly for simulating the air cooler to be in different environment temperatures, and a heat exchange liquid constant temperature assembly, the heat exchange liquid constant-temperature assembly is used for regulating heat exchange liquid of the air cooler to be in a constant-temperature state, and is arranged between a liquid inlet and a liquid outlet of the air cooler to form a heat exchange liquid circulation loop; the test method comprises the following specific test steps: simulating the working environment of the air cooler, testing the heat dissipating capacity of the air cooler, and correcting the actual heat dissipating capacity of the air cooler in different working environments. According to the invention, the current situation that the heat exchange performance of the air cooler at different altitudes is difficult to test and cannot be tested in a low-altitude area is solved, and meanwhile, the test system has the advantages of simple structure, convenience in operation, reasonable test method, high test accuracy and the like.

Description

Technical Field

[0001] The present invention relates to a test system and method for heat exchange performance, and more particularly to a test system and method for heat exchange performance of an air cooler. Background Art

[0002] DC transmission projects can achieve the mutual conversion of large-capacity AC and DC electric energy, and have the advantages of large transmission power, high social benefits, and significant economic benefits. As an important part of the main grid of the national power grid, the cross-regional DC transmission system is an important strategic channel for the optimal allocation of power resources on a larger scale. As the core equipment of the DC transmission project, the converter valve plays an important role in the AC-DC conversion in DC transmission, and its safety and reliability are the key to ensuring the long-term stable operation of the DC transmission system. To ensure the normal operation of main power equipment such as converter valves passing large currents in the converter station, the converter valve generally needs to be equipped with an efficient and stable auxiliary cooling system to ensure the timely dissipation of heat generated inside the equipment. As an important part of the converter valve system in the HVDC converter station, the heat exchange performance of the cooling system directly affects the safe and stable operation of the converter equipment.

[0003] The altitude of DC transmission projects is continuously increasing, and the project construction faces problems such as complex geological terrain and harsh natural environment. There is a lack of experience in the design and construction of extra-high voltage DC projects at high altitudes, and the environmental adaptability of the main equipment, the converter valve and the supporting valve cooling system, needs to be improved. To meet the urgent needs of project construction and equipment development, it is necessary to carry out experimental research on the heat dissipation performance of the air cooler, a key equipment of the valve cooling system in converter stations at high altitudes. Currently, the heat dissipation performance data of the air coolers used in projects are for conventional altitudes (less than 1000 meters). If air coolers for high altitudes need to be selected, the heat dissipation capacity of the air coolers at high altitudes is theoretically converted. A finalized air cooler does not have measured heat exchange performance test data at different altitudes. Summary of the Invention

[0004] The object of the present invention is to provide a test system and method for heat exchange performance of an air cooler, which solves the current situation that it is difficult to test the heat exchange performance of air coolers at different altitudes and cannot be tested in low-altitude areas. At the same time, the test system is not only simple in structure, but also convenient to operate, and the test method is reasonable and has high test accuracy.

[0005] To achieve the above object, the first technical solution of the present invention is: a test system for heat exchange performance of an air cooler, the innovation of which lies in: including:

[0006] A pneumatic simulation circuit, which is used to simulate test environment scenarios under different air pressures. The pneumatic simulation circuit includes an air inlet pump and an air extraction pump. The air outlet of the air inlet pump is connected to a sealed equipment room equipped with an air cooler, and the air extraction port of the air extraction pump is connected to the sealed equipment room.

[0007] A heat exchange liquid constant temperature assembly, which is used to control the heat exchange liquid of the air cooler to be in a constant temperature state. The heat exchange liquid constant temperature assembly is arranged between the liquid inlet and outlet of the air cooler and forms a heat exchange liquid circulation loop.

[0008] The heat exchange liquid constant temperature assembly includes a heat exchange liquid temperature adjustment loop and a heat exchange liquid heating loop.

[0009] The heat exchange liquid temperature adjustment loop includes a circulating pump group and a heat exchange liquid container. The outlet of the circulating pump group is connected to the liquid inlet of the air cooler, and the inlet of the circulating pump group is connected to the liquid outlet pipeline of the heat exchange liquid container.

[0010] The heat exchange liquid heating loop includes a first heater tank and a second heater tank connected in series. The heat exchange liquid container is connected to the second heater tank, and the first heater tank is connected to the liquid outlet of the air cooler.

[0011] A temperature simulation assembly, which is used to simulate test environment scenarios under different temperatures. The temperature simulation assembly includes an air heater and a cooler arranged in the sealed equipment room.

[0012] In the above first technical solution, the circulating pump group is composed of two parallel circulating pumps P01 and P02, and the motor of each circulating pump is configured with a frequency converter. The flow rate adjustment ranges of the circulating pump P01 and the circulating pump P02 are different, and maintenance valves are arranged before and after the circulating pumps P01 and P02.

[0013] In the above first technical solution, each tank of the first heater tank and the second heater tank is configured with four groups of heaters, and any one group of heaters among all the heaters is a heater with adjustable heating power, and the remaining heaters are all heaters with fixed heating power.

[0014] In the above first technical solution, temperature transmitters TT01 and TT02 are arranged on the pipeline connecting the liquid inlet of the air cooler and the circulating pump group for real-time monitoring of the inlet liquid temperature. Temperature transmitters TT21 and TT22 for real-time monitoring of the outlet liquid temperature are arranged at the liquid outlet of the air cooler, and a flow transmitter FIT01 for real-time monitoring of the flow rate is arranged.

[0015] A temperature transmitter for real-time monitoring of the temperature of the heated liquid is arranged at the liquid outlet of the first heater tank.

[0016] In the first technical solution described above, pressure gauges for real-time monitoring of the inlet pressure and the outlet pressure are respectively provided at the liquid inlet and the liquid outlet of the air cooler.

[0017] In the first technical solution described above, a heat preservation layer is provided on the outer periphery of the heat exchange liquid container to reduce the heat loss of the heat exchange liquid.

[0018] In the first technical solution described above, a liquid level gauge is further provided on the heat exchange liquid container to measure the liquid level height of the heat exchange liquid.

[0019] In the first technical solution described above, the air pressure simulation circuit further includes air pressure transmitters PT01 and PT02 which are arranged in the sealed equipment room and used for monitoring the real-time air pressure.

[0020] In the first technical solution described above, the temperature simulation assembly further includes air temperature transmitters TT11 and TT12 which are arranged in the sealed equipment room and used for monitoring the real-time temperature.

[0021] To achieve the above object, the second technical solution of the present invention is: a method for testing the heat exchange performance of an air cooler, and its innovation lies in: the specific test steps are as follows:

[0022] The sealed equipment room equipped with the air cooler is evacuated by the air extraction pump of the air pressure simulation circuit, and the internal pressure of the sealed equipment room is adjusted to the air pressure corresponding to different altitudes. At the same time, the air cooler is simulated to be in the corresponding ambient temperature at different altitudes through the temperature simulation assembly.

[0023] The heat exchange liquid is heated by the heat exchange liquid heating circuit of the heat exchange liquid constant temperature assembly and flows into the liquid inlet of the air cooler through the circulating pump group. At the same time, the inlet temperature t1 of the heat exchange liquid transported to the air cooler by the heat exchange liquid constant temperature assembly and the outlet temperature t2 of the air cooler are obtained, and the liquid delivery flow rate of the heat exchange liquid constant temperature assembly is adjusted to the designed flow rate Q of the air cooler. y ,

[0024] Combined with the designed value of the inlet temperature of the air cooler itself, the designed value of the inlet air temperature of the air cooler, and the air temperature of the air cooler under the corresponding temperature and altitude environmental conditions, the actual heat dissipation of the air cooler is corrected and calculated.

[0025] In the second technical solution described above, the heat dissipation of the air cooler is obtained according to the following formula:

[0026] P y = Q y ρ y C y (t1 - t2)

[0027] Among them, P y — Heat exchange capacity of the air cooler, unit: kW,

[0028] Q y — Design flow rate of the air cooler, unit: m 3 / h,

[0029] ρ y — Density is 1000 kg / m 3 ,

[0030] C y — Specific heat capacity of water, unit: kW h / kg·K,

[0031] t1 — Inlet liquid temperature of the air cooler, unit: °C,

[0032] t2 — Outlet liquid temperature of the air cooler, unit: °C.

[0033] In the above second technical solution, the actual heat dissipation of the air cooler is obtained according to the following formula:

[0034] P 试验 =(t′1 - t′2)P y / (t3 - t1)

[0035] Among them, t′2 — Design value of the inlet liquid temperature of the air cooler, unit: °C,

[0036] t′1 — Design value of the inlet air temperature of the air cooler, unit: °C,

[0037] t1 — Inlet liquid temperature of the air cooler, unit: °C,

[0038] t3 — Air temperature in the closed equipment room, unit: °C,

[0039] The obtained P 试验 is the actual heat dissipation of the air cooler under different working conditions at the same altitude, and the air cooler is under the design values of the inlet liquid temperature t′2 and the inlet air temperature t′1.

[0040] In the above second technical solution, the heating of the heat exchange liquid of the air cooler is divided into a full-power heating stage and a compensation heating stage,

[0041] Among them, the specific process of the full-power heating stage is: using the heat exchange liquid heating circuit to heat the heat exchange liquid from the initial inlet liquid temperature t0 to the set inlet liquid temperature t1 at full power, and real-time monitoring the heat exchange liquid temperature at any moment. When the heat exchange liquid reaches the inlet liquid temperature t1, stop running and obtain the output efficiency of the heat exchange liquid heating circuit,

[0042] The specific process of the compensation heating stage is as follows: According to the output efficiency of the heat exchange liquid heating circuit, the power to be compensated to maintain the set inlet liquid temperature t1 is obtained and used as the initial value of the output power of the heat exchange liquid heating circuit. After a delay time, it is judged whether the current inlet liquid temperature reaches the set inlet liquid temperature t1. Negative feedback regulation is carried out in three intervals according to the difference between the set inlet liquid temperature t1 and the actual inlet liquid temperature, so that the actual inlet liquid temperature is maintained at the set inlet liquid temperature t1 to meet the inlet liquid temperature requirement during the heat exchange performance test of the air cooler.

[0043] In the above second technical solution, during the full-power heating stage, the inlet liquid temperature t1 of the air cooler, the intermediate temperature of the air cooler inlet liquid (t1 - Δt), and the difference between the inlet liquid temperature t1 of the air cooler is Δt are preset. The time T1 required for the initial inlet liquid temperature t0 to reach the intermediate temperature (t1 - Δt) and the outlet liquid temperature t4 of the air cooler at this time, as well as the time T2 required for the intermediate temperature t1 - Δt to reach the inlet liquid temperature t1 and the corresponding outlet liquid temperature t2 of the air cooler are obtained. According to the system heat balance relationship, the following formula can be obtained:

[0044] C y m y (t1 - Δt - t0) + Q y ρ y (t1 - Δt - t4)T1 = ηP h T1

[0045] C y m y Δt + Q y ρ y (t1 - t2)T2 = ηP h T2

[0046] In the formula

[0047] η —— The conversion efficiency of the power of the heat exchange liquid heating circuit,

[0048] m y —— The mass of the heat exchange liquid in the pipeline, unit: kg,

[0049] P h —— The maximum power of the heat exchange liquid heating circuit, unit: kW,

[0050] Δt —— The difference between the intermediate temperature of the air cooler inlet liquid and the inlet liquid temperature, unit: °C,

[0051] t4 —— The outlet liquid temperature of the air cooler corresponding to the intermediate temperature of the air cooler inlet liquid (t1 - Δt) during the test, unit: °C,

[0052] T1 —— The time required for the inlet liquid temperature to rise from the initial temperature t0 to the intermediate temperature t1 - Δt, unit: h,

[0053] T2 - The time required for the inlet liquid temperature to rise from the intermediate temperature t1 - Δt to the inlet liquid temperature t1, with the unit of h. The conversion efficiency of the electric heater can be obtained by solving as

[0054]

[0055] Obtain the power P to be compensated to maintain the inlet liquid temperature ref

[0056]

[0057] The above-mentioned power P ref Is set as the initial value of the output power of the heat exchange liquid heating circuit;

[0058] When the difference between the actual inlet liquid temperature of the air cooler and the set inlet liquid temperature t1 is less than 2°C, the heat exchange liquid heating circuit performs PID power control,

[0059] When the difference between the actual inlet liquid temperature and the set inlet liquid temperature t1 is greater than 2 - 5°C, one set of fixed power heaters in the heat exchange liquid heating circuit is put into or taken out of service,

[0060] When the difference between the actual inlet liquid temperature and the set inlet liquid temperature t1 is greater than 5°C, two sets of fixed power heaters in the heat exchange liquid heating circuit are put into or taken out of service, so as to realize the fast - slow switching control of the heaters in the heat exchange liquid heating circuit based on the temperature difference, and meet the requirement of maintaining the actual inlet liquid temperature at the set inlet liquid temperature t1.

[0061] The positive effects of the present invention are:

[0062] (1) The present invention can adjust the air temperature and air pressure in the closed equipment room, and can realize the heat exchange performance test of the air cooler under different ambient temperatures and different altitudes, greatly improving the accuracy and efficiency of the heat exchange performance test of the air cooler;

[0063] (2) The circulating pump group configured in the present invention adopts a variable frequency control method, and can realize the experimental test of the heat exchange performance of a single air cooler under different flow rates;

[0064] (3) Compared with the traditional heat exchange performance test of the air cooler, which can only test one fan unit, the present invention can realize the heat exchange performance test of a single air cooler. The single - unit heat exchange performance test is consistent with the engineering application conditions, and the test results are more accurate.

[0065] (4) The present invention proposes a control strategy for the inlet water temperature of the air cooler based on the staged output of the heater power, which can accurately and quickly adjust the inlet water temperature of the air cooler and test the heat exchange performance of the air cooler. Brief Description of the Drawings

[0066] Figure 1 is a schematic structural diagram of the heat transfer performance test system of the air cooler of the present invention;

[0067] Figure 2 is a flowchart of the heat transfer performance test method of the air cooler of the present invention;

[0068] Figure 3 is a flowchart of the heat transfer liquid heating control strategy of the present invention. Detailed implementation manners

[0069] The present invention will be further described below in conjunction with the accompanying drawings and the given embodiments, but is not limited thereto.

[0070] Embodiment 1

[0071] As Figure 1 shown, a heat transfer performance test system of an air cooler includes:

[0072] A gas pressure simulation loop 1, which is used to simulate the test environment scenarios under different gas pressures. The gas pressure simulation loop 1 includes an air inlet pump 11 and an air extraction pump 12. The air outlet of the air inlet pump 11 is connected to a sealed equipment room C61 equipped with an air cooler, and the air extraction port of the air extraction pump 12 is connected to the sealed equipment room C61.

[0073] A heat transfer liquid constant temperature assembly 2, which is used to regulate the heat transfer liquid of the air cooler to be in a constant temperature state. The heat transfer liquid constant temperature assembly 2 is arranged between the liquid inlet and outlet of the air cooler and forms a heat transfer liquid circulation loop.

[0074] The heat transfer liquid constant temperature assembly 2 includes a heat transfer liquid temperature regulation loop 21 and a heat transfer liquid heating loop 22.

[0075] The heat transfer liquid temperature regulation loop 21 includes a circulating pump group 211 and a heat transfer liquid container 212. The outlet of the circulating pump group 211 is connected to the liquid inlet of the air cooler, and the inlet of the circulating pump group 211 is connected to the outlet pipeline of the heat transfer liquid container 212.

[0076] The heat transfer liquid heating loop 22 includes a first heater tank 221 and a second heater tank 222 connected in series. The heat transfer liquid container 212 is connected to the second heater tank 222, and the first heater tank 221 is connected to the liquid outlet of the air cooler.

[0077] A temperature simulation assembly 3, which is used to simulate the test environment scenarios under different temperatures. The temperature simulation assembly 3 includes four groups of air heaters 31 and four groups of refrigerators 32 arranged in the sealed equipment room.

[0078] Further, asFigure 1 As shown, in order to conduct experimental tests on the heat exchange performance of a single air cooler at different flow rates, the circulating pump group 211 is composed of two parallel circulating pumps P01 and P02, and the motor of each circulating pump is equipped with a frequency converter. The flow rate adjustment ranges of the circulating pumps P01 and P02 are different, and maintenance valves V001, V002, V003, and V004 are respectively arranged before and after the circulating pumps P01 and P02. Among them, the circulating pump PO1 realizes flow rate adjustment of 0 - 50 m 3 / h, and the circulating pump PO2 realizes flow rate adjustment of 50 - 100 m 3 / h.

[0079] Furthermore, as Figure 1 shown, in order to meet the test requirements of different heat exchange amounts, each tank of the first heater tank 221 and the second heater tank 222 is equipped with four groups of heaters, and any one group of heaters among all the heaters is a heater whose heating power can be adjusted within the range of 0 - 90 KW, and the remaining heaters are all heaters with fixed heating power. The present invention can start and stop the eight groups of heaters in groups, so that the first heater tank 221 and the second heater tank 222 connected in series can meet the test requirements of heat exchange amounts within the range of 0 - 720 KW.

[0080] Furthermore, for further optimization of the heating structure, the first heater tank 221 of the present invention is provided with heaters H11, H12, H13, and H14, the second heater tank 221 is provided with heaters H15, H16, H17, and H18, and drain valves V615 and V616 are respectively arranged at the bottom of the heater tanks, and maintenance valves V011, V012, and V013 are respectively arranged before and after.

[0081] Furthermore, as Figure 1 shown, in order to be able to obtain the inlet liquid temperature, outlet liquid temperature, and heat exchange liquid flow rate of the air cooler in real time, temperature transmitters TT01 and TT02 are arranged on the pipeline connecting the inlet of the air cooler and the circulating pump group 211 for real-time monitoring of the inlet liquid temperature, temperature transmitters TT21 and TT22 for real-time monitoring of the outlet liquid temperature are arranged at the outlet of the air cooler, and a flow transmitter FIT01 for real-time monitoring of the flow rate is arranged.

[0082] Furthermore, as Figure 1 shown, in order to obtain the inlet pressure and outlet pressure of the air cooler, be able to timely adjust the inlet or outlet pressure, and prevent the pressure from not meeting the technical requirements, pressure gauges for real-time monitoring of the inlet pressure and outlet pressure are respectively arranged at the inlet and outlet of the air cooler.

[0083] Meanwhile, in order to facilitate the monitoring of the inlet liquid temperature flowing into the liquid inlet of the air cooler, a temperature transmitter TT03 for real-time monitoring of the temperature of the heated liquid is provided at the liquid outlet of the first heater tank 221.

[0084] Furthermore, as Figure 1 shown, in order to prevent the loss of the flow rate of the heat exchange liquid, a heat preservation layer is provided on the outer periphery of the heat exchange liquid container 212 to reduce the heat loss of the heat exchange liquid. At the same time, a liquid level gauge LIT01 is also provided on the heat exchange liquid container 212 to measure the liquid level height of the heat exchange liquid, facilitating timely liquid replenishment. A drain valve V013 for conveniently discharging or replacing the heat exchange liquid is also provided at the bottom of the heat exchange body container 212.

[0085] Furthermore, as Figure 1 shown, in order to monitor the air pressure in the sealed equipment room, the air pressure simulation circuit 1 further includes pressure transmitters PT01 and PT02 provided in the sealed equipment room and used to monitor the real-time air pressure.

[0086] Furthermore, as Figure 1 shown, in order to monitor the temperature state of the sealed equipment room, the temperature simulation assembly 3 further includes air temperature transmitters TT11 and TT12 provided in the sealed equipment room and used to monitor the real-time temperature.

[0087] The heat exchange liquid of the air cooler described in the present invention is usually a water medium.

[0088] Embodiment 2

[0089] As Figure 2 , 3 shown, a method for testing the heat exchange performance of an air cooler specifically includes the following testing steps:

[0090] Step a: Simulate the working environment of the air cooler

[0091] The specific process is as follows: The sealed equipment room equipped with the air cooler is evacuated by the air extraction pump 12 of the air pressure simulation circuit 1, and the internal pressure of the sealed equipment room is adjusted to the air pressure corresponding to different altitudes. At the same time, the temperature simulation assembly 3 simulates the ambient temperature of the air cooler at different altitudes.

[0092] Specifically, through the following corresponding table of altitude and relative atmospheric pressure, the start and stop of the air inlet pump 11 and the air extraction pump 12 are controlled to meet the altitude test conditions required for the test:

[0093] Altitude / m Relative atmospheric pressure / Pa <![CDATA[Relative air density / (kg·m 3 )]]> 0 1 1.000 1000 0.881 0.903 2000 0.774 0.813 2500 0.724 0.770 3000 0.677 0.730 4000 0.591 0.653 5000 0.514 0.583

[0094] Step b: Test the heat dissipation of the air cooler

[0095] The specific process is as follows: on the premise of implementing step a, the heat exchange liquid is heated through the heat exchange liquid heating circuit 22 of the heat exchange liquid constant temperature assembly 2 and flows into the liquid inlet of the air cooler through the circulating pump group 211. At the same time, the liquid inlet temperature t1 of the heat exchange liquid transported from the heat exchange liquid constant temperature assembly 2 to the air cooler and the liquid outlet temperature t2 of the air cooler are obtained, and the liquid delivery flow rate of the heat exchange liquid constant temperature assembly 2 is adjusted to the designed flow rate Q of the air cooler y , and the heat dissipation of the air cooler is obtained according to the following formula

[0096] P y =Q y ρ y C y (t1 - t2)

[0097] Among them, P y —The heat exchange amount of the air cooler, unit: kW,

[0098] Q y —The designed flow rate of the air cooler, unit: m 3 / h,

[0099] ρ y —The density is 1000 kg / m 3 ,

[0100] C y —The specific heat capacity of water, unit: kW h / kg·K,

[0101] t1—the liquid inlet temperature of the air cooler, unit: °C,

[0102] t2—the liquid outlet temperature of the air cooler, unit: °C,

[0103] Step c. Correct the actual heat dissipation of the air cooler under different working environments

[0104] The specific process is as follows: combining the designed value of the liquid inlet temperature of the air cooler itself and the designed value of the inlet air temperature of the air cooler, and the air temperature in the enclosed equipment room under the corresponding temperature and altitude environmental conditions of the air cooler in step a, and correcting and calculating the actual heat dissipation of the air cooler according to the following formula, that is

[0105] P 试验 =(t′1 - t′2)P y / (t3 - t1)

[0106] Among them, t′2—the designed value of the liquid inlet temperature of the air cooler, unit: °C,

[0107] t′1—the designed value of the inlet air temperature of the air cooler, unit: °C,

[0108] t1—the inlet liquid temperature of the air cooler, unit: °C,

[0109] t3—the air temperature in the enclosed equipment room, unit: °C,

[0110] The obtained P 试验 is the actual heat dissipation of the air cooler under different working conditions at the same altitude, and the air cooler is at the designed inlet liquid temperature t′2 and the designed inlet air temperature t′1, thereby completing the heat transfer performance test of the air cooler.

[0111] Furthermore, in step a, the heating of the heat transfer liquid of the air cooler is divided into a full-power heating stage and a compensation heating stage.

[0112] Among them, the specific process of the full-power heating stage is: all heaters are started, and the heat transfer liquid heating circuit 22 is used to heat at full power at the fastest speed to raise the temperature, so that the heat transfer liquid is heated from the initial inlet liquid temperature t0 to the set inlet liquid temperature t1, and the temperature of the heat transfer liquid at any moment is monitored in real time. When the heat transfer liquid reaches the inlet liquid temperature t1, stop running, and obtain the output efficiency of the heat transfer liquid heating circuit 22.

[0113] The specific process of the compensation heating stage is: according to the output efficiency of the heat transfer liquid heating circuit 22, obtain the power required to maintain at the set inlet liquid temperature t1 as the initial value of the output power of the heat transfer liquid heating circuit 22. After a delay time, judge whether the current inlet liquid temperature reaches the set inlet liquid temperature t1, and perform negative feedback adjustment in three intervals according to the difference between the set inlet liquid temperature t1 and the actual inlet liquid temperature, so that the actual inlet liquid temperature is maintained at the set inlet liquid temperature t1 to meet the inlet liquid temperature requirements during the heat transfer performance test of the air cooler.

[0114] Furthermore, as Figure 3 shown, during the full-power heating stage, the inlet liquid temperature t1 of the air cooler, the intermediate temperature t1 - Δt of the air cooler inlet, and the difference between the inlet liquid temperature t1 of the air cooler is Δt (Δt is generally set to 3 - 5 °C) are preset. Obtain the time T1 required for the initial inlet liquid temperature t0 to reach the intermediate temperature t1 - Δt and the outlet liquid temperature t4 of the air cooler at this time, as well as the time T2 required to reach the inlet liquid temperature t1 from the intermediate temperature t1 - Δt and the corresponding outlet liquid temperature t2 of the air cooler. According to the system heat balance relationship, the following formula can be obtained:

[0115] C y m y (t1 - Δt - t0) + Q y ρ y (t1 - Δt - t4)T1 = ηP h T1

[0116] C y my Δt + Q y ρ y (t1 - t2)T2 = ηP h T2

[0117] In the formula

[0118] η —— The conversion efficiency of the power of the heat exchange liquid heating circuit

[0119] m y —— The mass of the heat exchange liquid in the pipeline, unit: kg

[0120] P h —— The maximum power of the heat exchange liquid heating circuit, unit: kW

[0121] Δt —— The difference between the intermediate temperature of the liquid entering the air cooler and the inlet liquid temperature, unit: °C

[0122] t4 —— The outlet liquid temperature of the air cooler corresponding to the intermediate temperature (t1 - Δt) of the liquid entering the air cooler during the test process, unit: °C

[0123] T1 —— The time required for the inlet liquid temperature to rise from the initial temperature t0 to the intermediate temperature t1 - Δt, unit: h

[0124] T2 —— The time required for the inlet liquid temperature to rise from the intermediate temperature t1 - Δt to the inlet liquid temperature t1, unit: h. The conversion efficiency of the electric heater can be obtained as

[0125]

[0126] Obtain the power P to be compensated to maintain the inlet liquid temperature ref

[0127]

[0128] The above power P ref Is set as the initial value of the output power of the heat exchange liquid heating circuit 22

[0129] When the difference between the actual inlet liquid temperature of the air cooler and the set inlet liquid temperature t1 is less than 2 °C, the heat exchange liquid heating circuit 22 performs PID power control

[0130] When the difference between the actual inlet liquid temperature and the set inlet liquid temperature t1 is greater than 2 - 5 °C, one set of fixed power heaters in the heat exchange liquid heating circuit 22 is put into or taken out

[0131] When the difference between the actual liquid inlet temperature and the set liquid inlet temperature t1 is greater than 5°C, two groups of fixed-power heaters in the heat exchange liquid heating circuit 22 are put into operation or withdrawn, so as to realize the fast-slow switching control of the heaters in the heat exchange liquid heating circuit 22 based on the temperature difference, and meet the requirement of maintaining the actual liquid inlet temperature at the set liquid inlet temperature t1.

[0132] Further, to verify the heat dissipation performance of the air cooler in a high-altitude environment, the type selection design of the air cooler to be tested is as follows in the table. The heat exchange capacity of the air cooler at different altitudes is tested respectively. The specific test method is as follows:

[0133] Design value of air inlet dry bulb temperature, °C 35.9 °C extreme ambient temperature Water inlet temperature of air cooler, °C 50.9℃ Water outlet temperature of air cooler, °C (design value) ≤41 Altitude, m 1000 m altitude Design value of heat transfer performance of single air cooler, kW 500 <![CDATA[Inlet flow rate of a single air cooler, m 3 / h]]> 44

[0134] The air pressure in the sealed equipment room is pumped out by an exhaust pump and gradually adjusted to the air pressure corresponding to an altitude of 1000 m. At the same time, the temperature of the sealed equipment room is gradually adjusted to 35.9°C by a temperature control device. The temperature difference fluctuates within 1 h - 2 h with a change of 0.5 K. The inlet water temperature of the air cooler is adjusted to 50.9°C, and the water flow rate is adjusted to the design flow rate of the cooler (44 m 3 / h). During the test process, parameters such as air pressure, the air temperature in the sealed equipment room (the inlet air temperature of the air cooler), the inlet water temperature t1 and the outlet water temperature t2 of the air cooler, and the water flow rate Q y are recorded.

[0135] Keeping the flow rate of the circulating medium (water) unchanged, the air pressure in the sealed equipment room is exhausted by an exhaust pump, and the corresponding air pressure is adjusted to 2000 m, 3000 m, 4000 m, and 5000 m respectively, so as to realize the heat dissipation test of the air cooler in different environments.

[0136] In summary, the air cooler heat exchange performance test system and test method of the present invention have the following advantages:

[0137] (1) The present invention can adjust the air temperature and air pressure in the sealed equipment room, and can realize the heat exchange performance test of the air cooler at different ambient temperatures and different altitudes, greatly improving the accuracy and efficiency of the heat exchange performance test of the air cooler;

[0138] (2) The circulating pump group configured in the present invention adopts a variable frequency control method, and can realize the test of the heat exchange performance of a single air cooler at different flow rates;

[0139] (3) Compared with the traditional heat exchange performance test of an air cooler, which can only test one fan unit, the present invention can realize the heat exchange performance test of a single air cooler. The single heat exchange performance test is consistent with the engineering application conditions, and the test results are more accurate.

[0140] (4) The present invention proposes a control strategy for the inlet water temperature of an air cooler based on the phased output of the heater power, which can accurately and quickly adjust the inlet water temperature of the air cooler and test the heat transfer performance of the air cooler.

[0141] Inspired by the above ideal embodiments according to the present invention, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. An air cooler heat transfer performance test system, characterized in that: Comprising: A pneumatic simulation circuit (1) for simulating test environment scenarios under different air pressures. The pneumatic simulation circuit (1) includes an air inlet pump (11) and an air extraction pump (12). The outlet of the air inlet pump (11) is connected to a sealed equipment room equipped with an air cooler, and the air extraction port of the air extraction pump (12) is connected to the sealed equipment room. A heat exchange liquid constant temperature assembly (2) for regulating the heat exchange liquid of the air cooler to be in a constant temperature state. The heat exchange liquid constant temperature assembly (2) is arranged between the liquid inlet and outlet of the air cooler to form a heat exchange liquid circulation loop. The heat exchange liquid constant temperature assembly (2) includes a heat exchange liquid temperature regulation circuit (21) and a heat exchange liquid heating circuit (22). The heat exchange liquid temperature regulation circuit (21) includes a circulation pump group (211) and a heat exchange liquid container (212). The outlet of the circulation pump group (211) is connected to the liquid inlet of the air cooler, and the inlet of the circulation pump group (211) is connected to the outlet pipeline of the heat exchange liquid container (212). The heat exchange liquid heating circuit (22) includes a first heater tank (221) and a second heater tank (222) connected in series. The heat exchange liquid container (212) is connected to the second heater tank (222), and the first heater tank (221) is connected to the liquid outlet of the air cooler. A temperature simulation assembly (3) for simulating test environment scenarios under different temperatures. The temperature simulation assembly (3) includes an air heater (31) and a cooler (32) arranged in the sealed equipment room.

2. The air cooler heat transfer performance test system according to claim 1, wherein: The circulation pump group (211) is composed of two parallel circulation pumps P01 and P02, and the motor of each circulation pump is configured with a frequency converter. The flow rate adjustment ranges of the circulation pumps P01 and P02 are different, and maintenance valves are provided before and after the circulation pumps P01 and P02.

3. The air cooler heat transfer performance test system according to claim 1, characterized in that: Each tank of the first heater tank (221) and the second heater tank (222) is equipped with four groups of heaters, and any one group of heaters among all the heaters is a heater with adjustable heating power, and the remaining heaters are heaters with fixed heating power.

4. The air cooler heat transfer performance test system according to claim 1, wherein: Temperature transmitters TT01 and TT02 are provided on the pipeline connecting the liquid inlet of the air cooler and the circulation pump group (211) for real-time monitoring of the inlet liquid temperature. Temperature transmitters TT21 and TT22 for real-time monitoring of the outlet liquid temperature and a flow transmitter FIT01 for real-time monitoring of the flow rate are provided at the liquid outlet of the air cooler. A temperature transmitter for real-time monitoring of the temperature of the liquid after heating is provided at the liquid outlet of the first heater tank (221).

5. The air cooler heat transfer performance test system according to claim 1, wherein: Pressure gauges for real-time monitoring of the inlet pressure and outlet pressure are respectively provided at the liquid inlet and outlet of the air cooler.

6. The air cooler heat transfer performance test system according to claim 1, characterized in that: A heat insulation layer is provided on the outer periphery of the heat exchange liquid container (212) to reduce the heat loss of the heat exchange liquid.

7. The air cooler heat transfer performance test system according to claim 1, wherein: A liquid level gauge is also provided on the heat exchange liquid container (212) for testing the liquid level height of the heat exchange liquid.

8. The air cooler heat transfer performance test system according to claim 1, wherein: The air pressure simulation circuit (1) further includes pressure transmitters PT01 and PT02 arranged in the sealed equipment room and used for monitoring the real-time air pressure.

9. The air cooler heat transfer performance test system according to claim 1, characterized in that: The temperature simulation assembly (3) further includes air temperature transmitters TT11 and TT12 arranged in the sealed equipment room and used for monitoring the real-time temperature.

10. A method for testing the heat transfer performance of an air cooler, characterized in that: The specific test steps are as follows: The sealed equipment room equipped with an air cooler is evacuated by the air extraction pump (12) of the air pressure simulation circuit (1), and the air pressure corresponding to different altitudes is adjusted inside the sealed equipment room. At the same time, the air cooler is simulated to be in the corresponding ambient temperature at different altitudes through the temperature simulation assembly (3). The heat exchange liquid is heated through the heat exchange liquid heating circuit (22) of the heat exchange liquid constant temperature assembly (2), and flows into the liquid inlet of the air cooler through the circulating pump group (211). At the same time, the inlet liquid temperature t1 of the air cooler delivered by the heat exchange liquid constant temperature assembly (2) and the outlet liquid temperature t2 of the air cooler are obtained, and the liquid delivery flow rate of the heat exchange liquid constant temperature assembly (2) is adjusted to the designed flow rate Q of the air cooler y , Combined with the design value of the inlet liquid temperature of the air cooler itself, the design value of the inlet air temperature of the air cooler, and the air temperature of the air cooler under the corresponding temperature and altitude environmental conditions, the actual heat dissipation of the air cooler is corrected and calculated.

11. The air cooler heat transfer performance testing method according to claim 10, characterized in that: The heat dissipation of the air cooler is obtained according to the following formula: P y = Q y ρ y C y (t1 - t2) Among them, P y — Heat exchange capacity of the air cooler, unit: kW Q y — Design flow rate of the air cooler, unit: m 3 / h ρ y — with a density of 1000 kg / m 3 , C y — Specific heat capacity of water, unit: kW h / kg·K t1—the inlet liquid temperature of the air cooler, in °C. t2—the outlet liquid temperature of the air cooler, in °C.

12. The air cooler heat transfer performance testing method according to claim 10, characterized in that: The actual heat dissipation of the air cooler is obtained according to the following formula: P 试验 = (t′1 - t′2)P y / (t3 - t1) where t′2—the design value of the inlet liquid temperature of the air cooler, in °C. t′1—the design value of the inlet air temperature of the air cooler, in °C. t1—the inlet liquid temperature of the air cooler, in °C. t3—the air temperature in the sealed equipment room, in °C. The obtained P 试验 is the actual heat dissipation of the air cooler under different operating conditions at the same altitude, while the air cooler is at the designed inlet liquid temperature t′2 and the designed inlet air temperature t′1.

13. The air cooler heat transfer performance testing method according to claim 12, characterized in that: The heating of the heat exchange liquid of the air cooler is divided into a full-power heating stage and a compensation heating stage. Among them, the specific process of the full-power heating stage is: using the heat exchange liquid heating circuit (22) to heat the heat exchange liquid from the initial inlet liquid temperature t0 to the set inlet liquid temperature t1 at full power, and monitoring the temperature of the heat exchange liquid at any time. When the heat exchange liquid reaches the inlet liquid temperature t1, stop running and obtain the output efficiency of the heat exchange liquid heating circuit (22). The specific process of the compensation heating stage is: according to the output efficiency of the heat exchange liquid heating circuit (22), obtain the power required to maintain the set inlet liquid temperature t1 for compensation, and use it as the initial value of the output power of the heat exchange liquid heating circuit (22). After a delay time, judge whether the current inlet liquid temperature reaches the set inlet liquid temperature t1, and perform negative feedback adjustment in three intervals according to the difference between the set inlet liquid temperature t1 and the actual inlet liquid temperature, so that the actual inlet liquid temperature is maintained at the set inlet liquid temperature t1 to meet the inlet liquid temperature requirement during the heat exchange performance test of the air cooler.

14. The air cooler heat transfer performance test method according to claim 13, characterized in that: During the full-power heating stage, the inlet liquid temperature t1 of the air cooler, the intermediate temperature of the air cooler inlet (t1 - Δt), and the difference between the inlet liquid temperature t1 of the air cooler is Δt are preset. Obtain the time T1 required for the initial inlet liquid temperature t0 to reach the intermediate temperature (t1 - Δt) and the outlet liquid temperature t4 of the air cooler at this time, as well as the time T2 required to reach the inlet liquid temperature t1 from the intermediate temperature t1 - Δt and the corresponding outlet liquid temperature t2 of the air cooler. According to the system heat balance relationship, the following formula can be obtained: C y m y (t1 - Δt - t0)+Q y ρ y (t1 - Δt - t4)T1 = ηP h T1 C y m y Δt + Q y ρ y (t1 - t2)T2 = ηP h T2 In the formula η——Conversion efficiency of the power of the heat exchange liquid heating circuit m y —— Mass of the heat transfer liquid in the pipeline, unit: kg, P h —— The maximum power of the heat exchange liquid heating circuit, in kW Δt——Difference between the intermediate temperature of the liquid entering the air cooler and the liquid inlet temperature, unit: °C t4——Outlet liquid temperature of the air cooler corresponding to the intermediate temperature (t1 - Δt) of the liquid entering the air cooler during the test process, unit: °C T1——Time required for the liquid inlet temperature to rise from the initial temperature t0 to the intermediate temperature t1 - Δt, unit: h T2——Time required for the liquid inlet temperature to rise from the intermediate temperature t1 - Δt to the liquid inlet temperature t1, unit: h The conversion efficiency of the electric heater can be obtained by solving Obtain the power P required for compensation to maintain the inlet liquid temperature ref The above-mentioned power P ref is set to the initial value of the output power of the heat exchange liquid heating circuit (22); When the difference between the actual liquid inlet temperature of the air cooler and the set liquid inlet temperature t1 is less than 2°C, the heat exchange liquid heating circuit (22) performs PID power control When the difference between the actual liquid inlet temperature and the set liquid inlet temperature t1 is greater than 2 - 5°C, one set of fixed power heaters in the heat exchange liquid heating circuit (22) is put into or taken out of service When the difference between the actual liquid inlet temperature and the set liquid inlet temperature t1 is greater than 5°C, two sets of fixed power heaters in the heat exchange liquid heating circuit (22) are put into or taken out of service, so as to realize the fast - slow switching control of the heaters in the heat exchange liquid heating circuit (22) based on the temperature difference, and meet the requirement that the actual liquid inlet temperature is maintained at the set liquid inlet temperature t1

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